|an arrangement of five objects, as trees, in a square or rectangle, one at each corner and one in the middle.|
|a screen or mat covered with a dark material for shielding a camera lens from excess light or glare.|
|Paleocene (pā'lē-ə-sēn') Pronunciation Key
The earliest epoch of the Tertiary Period, from about 65 to 58 million years ago. During this time, the Rocky Mountains formed and sea levels dropped, exposing dry land in North America, Australia, and Africa. Many new types of small mammals evolved and filled the niches left empty after the extinctions that ended the Cretaceous Period. Soft-bodied squid replaced the ammonites as the dominant form of mollusk. See Chart at geologic time.